Moon and Saturn
The Moon scoots past an apt companion late this evening: the planet Saturn. They rise in mid-evening, with Saturn to the lower left of the Moon. Saturn looks like a bright golden star.
The planet is an appropriate companion because today is Saturn's day -- Saturday.
Unlike the day or year, the seven-day week isn't based on any astronomical cycle, so different cultures devised their own "weeks."
Astrologers in Babylon probably started the seven-day week around 2700 years ago, when they gave each day the name of one of the seven "planets" visible in the sky. At the time, Earth was considered the center of the universe, and the celestial objects that moved through the stars were all considered planets. That included the Sun, Moon, and the five true planets visible to the unaided eye -- Mercury, Venus, Mars, Jupiter, and Saturn.
The astrologers assigned a planet to preside over each hour of the day. They started with the Sun, then followed with the Moon and planets. Each day was assigned to the planet that presided over the day's first hour. So Saturn's day is followed by the Sun's day -- Sunday -- and so on.
English day name are based on Anglo-Saxon versions of the planet's names. After Sunday, there's Moon's Day -- Monday; then Tuesday, for Tiw, the Anglo-Saxon version of Mars. It's followed by the names for Mercury, Jupiter, and Venus, then back to Saturn -- on Saturday.
More about Saturn and the Moon tomorrow.
Script by Damond Benningfield, Copyright 2011
For more skywatching tips, astronomy news, and much more, read StarDate magazine.